在Windows批处理文件中将反斜杠更改为正斜杠 [英] Change backslash to forward slash in windows batch file
问题描述
我正在尝试在包含文件名和位置的变量中将所有反斜杠()转换为正斜杠(/).我已阅读并看到:
I'm trying to convert all backslashes () to forward slashes (/) in a variable which contains a file name and location. I've read about this and seen:
%variable:str1=str2%
和
set "var=%var:\=/%"
我尝试过的
，但是显然我做错了.
which I've attempted, but I'm obviously not getting it right.
这是我的.bat脚本的相关部分:
Here is the relevant section of my .bat script:
FOR %%f IN ("E:\myfiles\app1\data\*.csv") DO (
echo %%f
set "f=%%f:\=/%"
echo %%f
echo.
)
输出显示每个文件名列出两次.
The output show each filename listed twice.
即这行:
set "f=f:\=/%"
没有按照我想要的去做.有人可以看到我在做什么错吗?
is not doing what I want it to. Can anyone see what I am doing wrong?
推荐答案
在块语句(a parenthesised series of statements)中，解析整个块并然后执行.块中的任何%var%都将在解析该块时被该变量的值取代-在执行该块之前-相同的情况适用于FOR ... DO (block).
Within a block statement (a parenthesised series of statements), the entire block is parsed and then executed. Any %var% within the block will be replaced by that variable's value at the time the block is parsed - before the block is executed - the same thing applies to a FOR ... DO (block).
因此，IF (something) else (somethingelse)将在遇到IF时使用%variables%的值执行.
Hence, IF (something) else (somethingelse) will be executed using the values of %variables% at the time the IF is encountered.
克服此问题的两种常见方法是:1)使用setlocal enabledelayedexpansion并使用!var!代替%var%来访问更改后的var值，或2)调用子例程以使用更改值.
Two common ways to overcome this are 1) to use setlocal enabledelayedexpansion and use !var! in place of %var% to access the changed value of var or 2) to call a subroutine to perform further processing using the changed values.
因此请注意使用CALL ECHO %%var%%来显示更改后的var值.
Note therefore the use of CALL ECHO %%var%% which displays the changed value of var.
您的代码包含两个单独的变量，分别称为f.
Your code contains two separate variables called f.
第一个是称为f的循环控制元变量"，并由%%f引用.
The first is the loop-control 'metavariable' called f and referenced by %%f.
第二个是由set "f=..."语句建立的公共环境变量f.可以在block中使用%f% 但来访问此变量，它似乎保留了解析控制for时的值(实际上，任何%var%在解析时替换为var 当时的值)
The second is the common environment variable f which is established by the set "f=..." statement. This variable can be accessed by using %f% but within a block, it will appear to retain the value it had when the controlling for was parsed (in fact, any %var% is replaced at parse-time by the value of var at that time)
metavariables不能在子字符串或替换之类的字符串操作语句中使用，只能将常见的环境变量用于这些操作，因此需要将元变量f的值分配给环境变量f和然后执行环境变量f的字符串替换任务.
metavariables cannot be used in string-manipulation statements like substrings or substitutes, only common environment variables can be used for these operations, hence you need to assign the value of the metavariable f to the environment variable f and then perform the string-substitution task of the environment variable f.
当然，有一个转折，就是必须使用delayedexpansion和!var!语法来访问块中环境变量的修改后的值.
The twist, of course, is that you must use delayedexpansion and the !var! syntax to access the modified value of an environment variable within a block.
所以
setlocal enabledelayedexpansion
for...%%f...do (
echo %%f
set "f=%%f"
set "f=!f:\=/!"
echo !f!
)
echo just for demonstration %f% !f! %%f
这将以必需的方式设置f的值(当然，您始终可以更改名称以避免混淆...)
This sets the value of f in the required manner (of course, you could always change the name to avoid confusion...)
最后一行只是为了说明f所获取的最终值可以以%f%或!f!的形式在循环外部进行访问，并且%%f不在上下文中并显示为%f.
The last line is simply to show that the final value acquired by f can be accessed outside of the loop as either %f% or !f!, and that %%f is out-of-context and shown as %f.
没有delayedexpansion的另一种方法是
for...%%f...do (
echo %%f
set "f=%%f"
call set "f=%%f:\=/%%"
call echo %%f%%
)
echo just for demonstration %f% !f! %%f
区别在于使用call和加倍%，最后一行将显示!f!就是这样-一个字面值，因为在delayedexpansion模式之外，!只是另一个对cmd没有特殊意义的字符.
the difference being the use of call and doubling the %s, and the final line will show !f! as just that - a literal, since outside of delayedexpansion mode, ! is just another character with no special meaning to cmd.
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